Need help tuning for 03 Yukon 5.3 CNVRT to flex fuel

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Hello everyone. I currently have a 03 YUKON XL 5.3 that I would like to convert to flex fuel as gas prices are ridiculous here in California.

I have installed the typical Continental type FF sensor and ran the signal wire to pin 56 on the blue connector of the ECU. Changed everything I could find in the tune related to flex fuel. Ecu does not display ethanol content. If someone could help me out and look at the attached file to possibly see if I missed something bi or if I have done it wrong to begin with. Thanks in advance for the help.

[SiriusC1024]

Apparently you have to use an entirely different OS.

https://forum.hptuners.com/showthrea...ex-fuel-enable

Are you sure you'll be saving money? e85 would have to be less than 73% the price of 87 octane (e10) for it to make sense. I save money running e30, but that's because the price of premium gas makes it worth it.

[[email protected]]

Apparently you have to use an entirely different OS.

https://forum.hptuners.com/showthrea...ex-fuel-enable

Are you sure you'll be saving money? e85 would have to be less than 73% the price of 87 octane (e10) for it to make sense. I save money running e30, but that's because the price of premium gas makes it worth it.

I found a 02 Yukon flex in the repository but not sure how to flash the OS portion. Is there some guide or hints on how this is done? Rest of the calibration tables look the same in comparison. Thanks

[5FDP]

2002 is a P01 computer and your 2003 is a P59 controller, you can't flash that file.

[[email protected]]

2002 is a P01 computer and your 2003 is a P59 controller, you can't flash that file.

So I can look for 03 to 05 Yukon files? Still need to flash the OS as well? Any how to on how to flash the OS? Tia

[AnimateMe]

The file you need would be for an L59, VIN code Z (8th position of VIN). Common in 03-07 Tahoes and Yukons.

[SiriusC1024]

Attached is a Flex Fuel VIN Z from the repository. Idk if you're AWD or not. You may wish to browse around. FYI to check the VIN, OS, etc., you click on the button that looks like a page with a blue upside-down exclamation mark in the VCM Editor toolbar.

Use this tool to compare and then change the appropriate parameters in the attached file to match it to your vehicle. Injectors would be one of those, obviously.
https://www.gmforum.com/vindecoder.php

You have to write entire the tune file (save a full backup of yours first). That means that you'll have to pay for more credits to do so.

Then change your VIN.
https://www.hptuners.com/help/VCM-Ed...k%20Commit.%20

[[email protected]]

Attached is a Flex Fuel VIN Z from the repository. Idk if you're AWD or not. You may wish to browse around. FYI to check the VIN, OS, etc., you click on the button that looks like a page with a blue upside-down exclamation mark in the VCM Editor toolbar.

Use this tool to compare and then change the appropriate parameters in the attached file to match it to your vehicle. Injectors would be one of those, obviously.
https://www.gmforum.com/vindecoder.php

You have to write entire the tune file (save a full backup of yours first). That means that you'll have to pay for more credits to do so.

Then change your VIN.
https://www.hptuners.com/help/VCM-Ed...k%20Commit.%20

Thanks for the info. Will be back with the results in a couple of days.

[[email protected]]

Attached is a Flex Fuel VIN Z from the repository. Idk if you're AWD or not. You may wish to browse around. FYI to check the VIN, OS, etc., you click on the button that looks like a page with a blue upside-down exclamation mark in the VCM Editor toolbar.

Use this tool to compare and then change the appropriate parameters in the attached file to match it to your vehicle. Injectors would be one of those, obviously.
https://www.gmforum.com/vindecoder.php

You have to write entire the tune file (save a full backup of yours first). That means that you'll have to pay for more credits to do so.

Then change your VIN.
https://www.hptuners.com/help/VCM-Ed...k%20Commit.%20

THANK YOU. That worked and now up and running. Appreciate the help.

[SiriusC1024]

THANK YOU. That worked and now up and running. Appreciate the help.

You're most welcome

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UPDATE; Used the SUV this weekend to tow my drift car out to the upper desert and she performed beautifully. Seemed to have more torque uphill ran smoothly.

Noticed that the fuel gauge calibration is off a bit as the gauge shows lower than actual. Think there was a section for that in the tuning. Will check that out soon.

Overall satisfied with the conversion.

[2xLS1]

Those vehicles could have come with different size fuel tanks. Just compare the settings in the Fuel System tab to the ones in your vehicles original calibration and copy over any differences.

[Fast4.7]

You will need your stock tune and injectors come smog time.

[[email protected]]

Just an update,

It has been a year now and everything runs great. Vehicle has just passed CA smog check as well today with the tags due next month.

[SiriusC1024]

Hey awesome. Can't believe it's already been a year.